The present invention relates generally to electric or pneumatic power drivers. More particularly, the present invention relates to a power driver having a chuck that is constructed within the driver spindle.
Electric and pneumatic tool drivers are well known. Although twist drills are the most common tools on such drivers, the tools may also comprise screw drivers, nut drivers, burrs, mounted grinding stones and other cutting or abrading tools. Since the tool shanks may be of varying diameter or of polygonal cross section, the device is usually provided with a chuck that is adjustable over a relatively wide range. The chuck may be attached to the driver spindle by a threaded or tapered bore.
A variety of chucks for both hand and power drivers have been developed in the art. In an oblique jawed chuck, a chuck body includes three passageways disposed approximately 120□ apart from each other. The passageways are configured so that their center lines meet at a point along the chuck axis that is typically forward of the chuck. The passageways constrain three jaws which are moveable in the passageways to grip a cylindrical or polygonal tool shank displaced approximately along the chuck's center axis. The chuck includes a nut that rotates about the chuck center and that engages threads on the jaws so that rotation of the nut moves the jaws in either direction within the passageways. The body is attached to the spindle of a driver and is configured so that rotation of the body in one direction with respect to the nut forces the jaws into gripping relationship with the tool shank, while rotation in the opposite direction releases the gripping relationship. The chuck may be operated by a chuck key, or the sleeve may be rotated by hand in a keyless configuration. An example of a keyless chuck is disclosed in U.S. Pat. No. 5,125,673 commonly assigned to the present Assignee and the entire disclosure of which is incorporated by reference herein. Various configurations of keyless chucks are known in the art and are desirable in a variety of applications.